6.5 Specialty Slide Rules
While the majority of slide rules consisted of logarithmic scales for performing general calculations, many were designed for specific computations for very specific tasks. Just as a modern computer program might be used to perform a repeated calculation rather than typing in a series of similar computations again and again on an electronic calculator, special slide rules were developed for repeated calculations such as those found in the fields of electricity and electronics, chemistry, surveying, and so forth. Below are lists of slide rules that may be considered specialty rules in that they have scales specifically designed for use in a particular application or for a particular profession. Approximately 13% of the slide rules in the collection – 39 in total – are specialty rules.
The size Lx listed in these tables is the length in inches of the item’s greatest dimension, and not necessarily the length of a scale’s decade.
Aviation Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Felsenthal | AN 5837-1 | 1943 | C | 8 | Altitude Correction Computer; B/W main spiral scale, with fluorescent markings; WWII | |
| Felsenthal | D-4 | 1944 | C | 4 | Time Distance Computer Type D-4; WWII device; Property of U.S. Army Air Forces; fluorescent numbers on black background | |
| Felsenthal | FAA-95 | 1950-1955 | C | 8 | MB-1 Computer, Air Navigation, True Airspeed and Altitude; true altitude correction spiral on back | |
| Felsenthal | Dial-A-Con | 1968 | C | 7 | Flight computer, Type E6B, with instruction manual (by A. Fuchs), and vinyl case |
Chemical Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Nestler | 33 Chemiker | 1924-1933 | L | 10 | Early Chemical Rule, Albert Nestler A.G. LAHRi/B D.R. Patent Germany; Pickworth Data Slip on back; wide 1-line cursor | |
| Hemmi | 257 | 1956 | L | 10 | Chemical Engineering; owner Frank Banks of CA |
Electro and Electronics Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| K&E | 4133 | 1913-1922 | L | 8 | Roylance Electrical Slide Rule, mahogany, early release; prod mark 255; used and in poor condition; missing original 3-hairline cursor | |
| Faber-Castell | 379 | 1923 | L | 5 | Electro rule; nice condition; pearwood; Made in Bavaria and date marks 3 and 12 on back; V and Eff scales in well; W gauge on C | |
| Hemmi | 80/3 |
|
1935 | L | 10 | Electro; tables on back and text on box in French |
| K&E | N4133 | 1944 | L | 8 | Roylance Electrical Slide Rule, mahogany; 3-hairline cursor; scale set #3; original case and box | |
| K&E | 4139 | 1946 | L | 10 | Cooke Radio Slide Rule; Case: Polyphase Duplex DeciTrig 4071-3S | |
| Pickett | N-515-T | 1958-62 | L | 10 | Electronics model; leather case, strap – great condition; Cleveland Institute of Electronics | |
| Pickett | N-515-T | 1958-62 | L | 10 | Electronic; basically new-in-box; leather case, strap – great condition; Cleveland Institute of Electronics | |
| Concise | 380 |
|
1959-1966 | C | 4 | Radio Computer, with instruction sheet; Concise Co., Ltd. |
Engraving/Proportions Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| P.A.S. Co. | Engraving Rule |
|
1928 | L | 7 | Engraving Proportion Scale; sold by Art Brown & Bro. Inc. NewYork; similar to Hyde Optical Slide Rule at ISRM |
| Lawrence | 10-C | 1935-1938 | L | 5 | Lawrence Engravers / Photographers Proportion Calculator; Wabash, IN | |
| noID | Engraving Rule |
|
1940 | L | 20 | 18 inch proportions rule, perhaps used in printing, engraving; maker? American Blueprint? (similar construction to U.S. Military Rule); A/B scales range from 1 to 30, 12 inches from 1 to 10 |
| Lawrence | 10-N |
|
1946 | L | 10 | Lawrence Printer’s Proportion Rule; Peru, IN |
| C-Thru | PS-79 |
|
1970 | C | 6 | Proportional Scale, from the estate of Johnny Craig, noted comic book artist |
Military Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Richardson | Model of 1917 | 1917-1918 | L | 18 | WW I military slide rule for ranging calculations; mahogany on brass; described in Richardson’s Slide Rule Simplified, 6th Ed.; made for J.H. Weil & Co., Phila. | |
| Sillcocks-Miller | M1 Slide Rule No. 547 | 1942 | C | 12 | Military ballistic slide rule; angles in mils (800 mils = 45 deg); designed by Robert Crichlow | |
| American Blueprint | Military | 1948-1957 | L | 12 | US Military slide rule, for field artillery problems | |
| Pickett | 14 | 1958-1962 | L | 10 | U.S. military rule; well-worn leather case |
Spring Design Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Sandish | Spring Calculator |
|
1940 | L | 20 | apparent home-made dual-slide spring calculation slide rule; traced by F. Sandish; original owner M.L. Rowe |
| Baetzmann | Spring Calculator | 1941 | L | 17 | Spring Load Calculations slide rule; large format 17 in x 2.5 in x 0.75 in; two slides on front, one on back; owner (maker?) R. K. Baetzmann, 1941 | |
| J.B. Carroll | Associated Spring M110 | 1952 | L | 10 | early version, made for Associated Spring; no cursor | |
| Acu-Rule | Connecticut Spring | 1955 | L | 10 | Spring design calculations rule,version 3, made for Connecticut Spring Corp. |
Stadia (Surveying) Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Kolesch | 2713 Stadia | 1905-1911 | L | 10 | stadia rule, 360deg, D.R.Patent No. 173660, likely made by Nestler; advertised in 1907 How to use Slide Rules; suede leather case; owner Everett Gowty, Perry, OK | |
| K&E | 4100 | 1915-1922 | L | 10 | Stadia rule, early model, for use in surveying; instructions on back; all-glass cursor; prod marks 268 on end | |
| K&E | N4100 | 1938 | L | 10 | Stadia rule, for use in surveying; instructions on back; metal rimmed cursor | |
| Aristo | 958 | 1970 | L | 10 | Geodat 400g stadia rule; instructions (German), clip-on supports; 5-hairline cursor; box and 1364 insert |
Weight Calculation Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Novotni | Weight Calculator |
|
1935 | L | 15 | Novotni, but not marked as such; 13 inch o/a length; By-Products Steel Corporation; Commercial Trust Building, Philadelphia, Pa. |
| Pickett | N-550-T | 1962 | L | 10 | Warren-Knight Weight Rule 1373-ET; Label Style 3 with copyright 1962 |
Other Specialty Slide Rules
| Maker | Model | Year | Type | Lx | Note | |
|---|---|---|---|---|---|---|
| Richardson | GE Analizer |
|
1918 | L | 18 | General Electric Company Quantity Analizer; similar construction to Richardson/J.H.Weil Slide Rule of 1917; slots apparently for cursor on edges |
| Acu-Rule | Arel G-W Photo | 1946 | L | 10 | Goodchild-Whitney (G-W) Photo Slide Rule, with instruction book | |
| Lawrence | 10-D |
|
1946 | L | 10 | Lawrence Lumber Calculator; Peru, IN |
| Blundell Rules Limited | Radiac No. 1 | 1952-1956 | C | 5 | radiation exposure calculator; log log scales; reversible land/sea discs; instructions on back | |
| Pickett | N1040-ES | 1954 | L | 10 | Fisher Control Valve Sizing Rule; made for Fisher Governor Co, Marshalltown, Iowa | |
| Kahl Scientific | Culbertson Slide Rule | 1955 | C | 8 | Temperature, Depth, Salinity calcs; Designed by Margaret Culbertson for the U.S. Navy Electronics Lab; full instructions |
Below is a histogram of Specialty Slide Rules in the Collection as distributed over the decades of the 20th Century:
